This invention relates to a method and apparatus for temporarily increasing the transport capacity of the water supply system in case of a calamity, in which despite the occurrence of a calamity an amount of drinking water is to be transported to the service area of a pumping station or transport line which has failed.
For customers served by waterworks, it is of vital importance that during the occurrence of any calamity, the level of supply remains above a certain minimum. To that end, in the Netherlands, the VEWIN standards have been established.
The guideline for supply assurance as drawn up by the VEWIN reads: In case of failure of one element of the drinking water system, in centers of consumption, the residual supply capacity of the system must, on a daily basis, be greater than 75% of the maximum daily capacity. A calamity is defined as the failure of one element which cannot be repaired within 24 hours and has an effect on a large group of consumers.
To meet this requirement, waterworks must make provisions that make it possible to continue to supply drinking water during the protracted failure of a pumping station or transport line. In case of a calamity, therefore, an amount of drinking water must be transported to the service area of the pumping station or transport line which has failed.
The transport capacity of the residual mains system should then be anticipatorily increased if it is too small to enable supply of the required amount for supply assurance.
To solve this problem, for instance an additional transport line can be installed or an ancillary line with segmentation can be laid. However, both solutions are costly and disadvantageous to the water quality in the normal supply situation.
What may also be considered is to permanently arrange a fixed apparatus at a certain location for raising the pressure in the line and to connect it to the transport line. Thus, the transport function of the failing pumping station or pipe section can be partly taken over.
However, since in that case a large number of fixed apparatuses are needed, which moreover are not used in the normal supply situation, this solution is expensive and not economical.
The object of the invention is to provide a method and apparatus with which the drawbacks outlined are obviated. This object is achieved with a method wherein in case of a calamity at least one mobile apparatus for raising the pressure in the transport line is temporarily connected to the residual supply system, and with a mobile apparatus, evidently intended for and arranged for use in that method, having a transportable housing with a pump coupled to a motor comprising means for setting the pump on two sides into communication with a water transport line via connecting lines.
It is possible during a calamity to make a location suitable for receiving a mobile apparatus according to the invention. Preferably, a transport function which has fallen out is taken over, while in a relatively inexpensive manner a mobile apparatus according to the invention, which can be conveyed in a short time to predetermined locations and which can be rapidly connected to the water transport line in question, suffices.
It is noted that German Offenlegungsschrift 195 10 409 discloses an apparatus for increasing the pressure in a pipe system, which apparatus comprises a number of pumps, to be pre-mounted on a plate, if desired. The advantage of this apparatus is supposed to be that parts of the apparatus are easy to mount and dismount. It seems, however, that this advantage relates solely to the parts of an apparatus which itself forms part of a larger machine. No reference is made to a mobile apparatus for temporary use in a system of water transport lines.
It is further noted that U.S. Pat. No. 3,584,640 discloses a pneumatic water pump station comprising a housing with a pump coupled to a motor, arranged in a water reservoir. It is stated that the pump station is compact and easily transportable. The pump station is intended as an alternative to a water tank or pressure-water installation, which have a fixed function within a drinking water system. Although the pump station may in itself be easily transportable, it is intended for use in a permanent setup. Such a pump station with built-in water reservoir is not suitable as a mobile booster in the use of the method according to the invention.
It is noted, finally, that Patent Abstract of Japan, vol. 009, no. 290 (M-430) concerning the Japanese patent application with publication no. 60128979, discloses a high pressure pump on wheels, with a suction piece to be inserted in a storage tank and a high pressure conduit that can be connected to an injection nozzle or the like. As application for raising water pressure in a transport line of a water supply system, such a mobile pump is not suitable.